Year: 2014
Type: dissertation
Study design: Observational Study
Abstract: Adequate rest and periods of activity are important for maintaining physiological homeostasis, for the adaptive functioning of the stress-response systems, and they promote psychological well-being. However, knowledge on the associations of sleep and physical activity with stress system functioning, and of physical activity with psychiatric problems is limited especially in children and youth. This study was designed to address three research questions, (1) whether sleep is associated with cardiovascular function in 8-year-old children, (2) whether physical activity is associated with psychiatric problems in 8-year-old children, and (3) whether physical activity is associated with hypothalamic-pituitary-adrenocortical axis (HPAA) function in 8- and 12-year-old children. The participants came from an urban community-based cohort originally comprising 1049 infants born in 1998 in Helsinki, Finland. Sleep and physical activity were objectively measured using accelerometers. Sleep was also assessed using parent-reported questionnaire-based data. Of the 413 children invited to a follow-up, 321 participated at a mean age of 8.1 years. Of these, 231 to 274 were included in the analyses of sleep and ambulatory blood pressure, or cardiovascular reactivity to the Trier Social Stress Test for Children (TSST-C). The children s mothers and teachers filled in a questionnaire reporting common childhood psychiatric problems, and 199 children had valid data on physical activity and psychiatric problems from both observers. HPAA activity was measured via salivary cortisol concentrations, 252 of the children with valid data on physical activity had data on diurnal salivary cortisol, and 248 had data on salivary cortisol responses to the TSST-C. Later, of the 920 adolescents invited to a further follow-up, 451 participated at a mean age of 12.3 years. Of these, 283 adolescents with valid physical activity data provided data on diurnal salivary cortisol, and 272 adolescents provided data on salivary cortisol responses to a low-dose overnight dexamethasone suppression test (DST), a method used to study the individual physiological variation in HPAA feedback inhibition. In contrast with a wealth of evidence especially from adults, the results showed that sleep in healthy children was not associated with an unhealthy cardiovascular phenotype. Higher physical activity levels were associated with a lower probability for psychiatric problems in children as well as lower HPAA reactivity to psychosocial stress at 8 years of age. In addition, in early adolescence (12 years of age) physical activity was associated with lower morning cortisol levels in girls and higher HPAA suppression in response to the DST in boys. These results provide evidence on the health-related associations of sleep and physical activity in a community-based cohort of children. These findings offer insight into the influence of physical activity on physical and mental well-being, by suggesting that physical activity could promote health by moderating HPAA function. As the results are correlational in nature, further research using a prospective controlled methodology is called for. This study emphasizes the importance of sustaining and supporting high physical activity levels throughout childhood and adolescence.
Source: Työväentutkimus Vuosikirja
Author: Silja Martikainen
Language: English
Topic: Physical Activity and Health
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funders: John D. and Catherine T. MacArthur Foundation, Yrjö Jahnssonin Säätiö, Jalmari ja Rauha Ahokkaan Säätiö, European Science Foundation, Suomen Kulttuurirahasto, Juho Vainion Säätiö, Signe ja Ane Gyllenbergin Säätiö, Emil Aaltosen Säätiö, Lastentautien Tutkimussäätiö, Sigrid Juséliuksen Säätiö
OpenAlex ID: W1526755478